Lignin fragments rich in detached side-chain structures found in water-soluble LCC

The content of the glyceraldehyde-2-aryl ether-type structure in water-soluble lignin–carbohydrate complex (LCC) fractions, which were obtained from Japanese cedar and birch residual wood meal after milled wood lignin isolation, was determined by ozonation. Quite high amounts of the glyceraldehyde-2-aryl ether-type structure were found in water-soluble LCC fractions of both species; about 3–5 times higher than those of other fractions. This result, as well as the high content of the β-1 structure in these fractions shown in our previous reports, suggest that lignin in these fractions has the characteristics of endwise-type lignin, because the glyceraldehyde-2-aryl ether-type structure and β-1 structure are typical characteristics of this type of lignin fraction. These results are in good agreement with the generally accepted hypothesis that the glyceraldehyde-2-aryl ether-type structure and β-1 structure are generated at the same time by a radical coupling reaction. The results also indicated that these two structures are present in close proximity in the lignin.     

基于3S技术的森林城市景观结构分析

以福建省永安市为研究对象,基于3S技术手段,运用景观分析软件Fragstats4.1,计算不同水平上不同景观要素的特征值,对永安市现有城市景观和城市森林景观在类型水平和景观水平上的景观格局进行研究。结果表明:研究区各景观类型分布较为均匀,不存在明显的优势主体;城市森林整体分布不够均衡,研究区还未形成生态功能较为完善的城市森林结构。研究结果可为地区森林城市建设的可持续发展提供决策支持。     

三层实木复合地板背板含水率对其变形的影响

采用单因素试验法，探讨了三层结构实木复合地板背板的含水率对地板长度方向变形的影响。结果表明：背板含水率对地板的变形有明显影响，含水率过低或过高时复合地板的变形都较大；背板含水率可依据背板密度的大小而调整，但一般不得高于12％；背板一般使用针叶树材．允许使用软阉叶树材，但含水率的控制相对需严格。含水率控制适当是解决复合地板变形的重要方法之一。     

南瓜茶饮料不同风味加工技术研究

研究了以南瓜为原料，经热水2次浸提（1kg南瓜：4000ml水）所得南瓜母液，每100ml母液添加14g白沙糖、0.18g柠檬酸的甜酸型南瓜茶饮料和每100ml母液添加14g白砂糖、0.2g柠檬酸、0.09g食用盐配方而成的复合风味南瓜茶饮料的生产技术。     

生物多样性的形成、维持机制及其宏观研究方法

关于生物多样性的形成与维持机制 ,虽有众多假说 ,但均未形成完善的理论体系。不同的学者从不同的角度出发 ,研究了诸多生态因子与生物多样性的关系 ,得出了许多结论、导出了不少争议。本文主要简述了生物因子 (如生产力、生物量、种间关系、土壤微生物 )和非生物因子 (干扰与空间异质性、气候、土壤因子等 )与生物多样性之间的相互作用机理、人类活动对生物多样性的影响 ,以及在生物多样性影响机制研究中所用的 3S技术与数学方法。总之 ,我们应坚持综合作用的观念 ,从不同的时间和空间尺度、在不同的对象层次上 ,全面、深入地研究各类生物和非生物因子与生物多样性之间的相互作用机理 ,才能得出关于生物多样性的形成与维持机制的全面、完善的理论     

电力远程自动集中抄表系统

本文主要论述电力远程自动集中抄表系统的构成、特点以及系统的发展前景。     

南酸枣早实丰产栽培技术

南酸枣是南方重要的经济林、用材林、园林绿化树种。野生状态南酸枣10a挂果,20a进入盛果期。自2001年起,崇义县推广嫁接技术培育南酸枣,比野生南酸枣树提前6年挂果,提前12年进入盛果期。为以南酸枣果实为主的食品、饮料加工企业提供了原料保证,并具较好的经济效益、生态效益和社会效益。     

基于基因芯片的梨品种S基因型鉴定的技术方法

梨是典型的配子体自交不亲和植物,梨品种自交不亲和基因型(S基因型)确定的研究对于梨的栽培和遗传改良具有重要的意义.综合分析了运用杂交授粉试验、PCR-RFLP技术、DNA序列分析、cDNA克隆等技术在确定梨品种S基因型方面的优点和不足之处,提出了运用基因芯片技术确定梨品种S基因型的新方法,并分析了该技术的优势以及在梨品种S基因型确定方面的应用前景.     

猫尾草的价值与栽培技术

文章介绍了猫尾草的形态特征及其实用价值,并总结了其栽培管理技术.     

Seasonal dynamics of mineral N pools and N-mineralization in soils under homegarden trees in South Andaman,India

Agroforestry trees are now well known to play a central role in the build up of nutrients pools and their transformations similar to that of forest ecosystem, however, information on the potential of homegarden trees accumulating and releasing nitrogen (mineralization) is lacking. The present study reports seasonal variations in pool sizes of mineral N (NH₄⁺-N and NO₃⁻-N), and net N-mineralization rate in relation to rainfall and temperature under coconut (Cocos nucifera L.), clove (Eugenia caryophyllata Thunb) and nutmeg (Myristica fragrans Houtt. Nees) trees in a coconut-spice trees plantation for two annual cycles in the equatorial humid climate of South Andaman Island of India. Concentration of NH₄⁺-N was the highest during wet season (May–October) and the lowest during post-wet season (November–January) under all the tree species. On the contrary, concentration of NO₃⁻-N was the lowest in the wet season and the highest during the post-wet season. However, concentrations of the mineral N were the highest under the nutmeg and the lowest under the coconut trees. Like the pool sizes, mean annual mineralization was the highest under the nutmeg (561 mg kg⁻¹ yr⁻¹) and the lowest under the coconut trees (393 mg kg⁻¹ yr⁻¹). Rate of mineralization was the highest during the post-wet season and the lowest during the dry season (February–April) under all the tree species. High rainfall during the wet season, however, reduced the rate of nitrification under all the tree species. The mean annual mineralization was logarithmically related with rainfall amount and mean monthly temperature.